A SYNOPSIS OF THE APHIDIDAE 39 



39. Symydobius salicicorticis Essig 



Figure 74 



Essig, Pom. Jour. Ent., vol. 4, p. 731, 1912 (orig. dese.). 

 Record. Salix laevigata; Santa Paula (Essig). 



Together with specimens of Fullauwya saliciradicis Essig, this was 

 taken on willow along the Santa Clara River near Santa Paula in 

 August, 1911. The colonies are found on the bark near the surface 

 of the ground either just above or just below it. Essig reports that it 

 is preyed upon quite extensively by the larvae of an undetermined 

 species of syrphus fly. The author has had access to cotype specimens 

 in Essig 's collection. 



Group Lachnina Passerini 



Passerini, Gli Afidi, 1860. 



In this group there are included two tribes, Lachnini Del Guercio 

 and Pterocommini Wilson, following Wilson. Mordwilko places but 

 the one tribe Lachnini in this group, including the genus Pterocomma 

 Buckton in the tribe Chaitophori. However, to the author the group- 

 ing followed here seems more natural. The following key is adapted 

 in part from Borner (Sorauer, Pflanzenkrankheiten, vol. 3, p. 665, 

 1913) : 



Sixth antennal segment with a short, thick (thumb-like) projection. Cornicles 

 conical (fig. 91) or wart-like. Empodial hair short, and oftentimes indistin- 

 guishable (fig. 79) Tribe Lachnini 



Sixth antennal segment with a slender projection (VI spur) which is about as 

 long as the segment (VI base). Cornicles cylindrical or clavate (figs. 81, 82). 

 Empodial hair practically as long as the claws (fig. 80). Tribe Pterocommini 



Tribe Pterocommini Wilson 



Wilson, Ann. Ent. Soc. Am., vol. 8, pp. 347-358, 1915. 



This tribe, as considered by Wilson, contains but the one genus, 

 Pterocomma Buckton. In a former paper (Can. Ent., vol. 43, p. 384, 

 1910) he recognized two genera : the one, Melanoxantherium Schoute- 

 den, in which the cornicles were swollen or vasiform, and the other, 



